First Online: 06 August 2008Received: 25 July 2008Accepted: 06 August 2008

Abstract

A widespread and highly conserved family of apparently inactivated derivatives of archaeal B-family DNA polymerases is described. Phylogenetic analysis shows that the inactivated forms comprise a distinct clade among archaeal B-family polymerases and that, within this clade, Euryarchaea and Crenarchaea are clearly separated from each other and from a small group of bacterial homologs. These findings are compatible with an ancient duplication of the DNA polymerase gene followed by inactivation and parallel loss in some of the lineages although contribution of horizontal gene transfer cannot be ruled out. The inactivated derivative of the archaeal DNA polymerase could form a complex with the active paralog and play a structural role in DNA replication.

ReviewersThis article was reviewed by Purificacion Lopez-Garcia and Chris Ponting. For the full reviews, please go to the Reviewers- Reports section.

Electronic supplementary materialThe online version of this article doi:10.1186-1745-6150-3-32 contains supplementary material, which is available to authorized users.